Radio planning parameters used by network operators to install base stations are often based on information derived from radio propagation models which simulate coverage and capacity within the desired geographical space of service of the base station. For example, calibrated pathloss models can predict the EIRP (equivalent isotropically radiated power) in geographical space accurately. However, although the signal quality across a particular geographical area can be determined, the signal quality per user in time (e.g. during the course of a day or week) cannot be predicted. Therefore, since such models can only approximate radio conditions in an environment and traffic distribution in time and location, the radio planning parameters used by network operators to install base stations carry inherent inconsistencies and errors.
The coverage and capacity of a base station sector in its dominant geographical space of service is defined by the average signal to noise and interference ratio (SNR) levels encountered by the mobile devices of users served by the base station sector. Each mobile user establishes a discrete radio link with the sector base station, but all users are served by a finite amount of radio power in the 3-dimensional antenna radiation space. When users are located at the “cell-edge”, a lack of power (caused by excessive pathloss) and/or high interference can result in the underperformance of signal to noise and interference ratio (SNR) levels encountered by selected radio links in a sector's service area. Underperforming radio links in a sector's service area result in low average signal to noise and interference ratio (SNR) levels delivered by the base station sector in its dominant geographical space of service, thereby resulting in an underperforming base station investment for the network.
An uneven user distribution split in the base station sector dominant geographical space of service (i.e. other than 50/50 about the central antenna sector radiation heading) can significantly impact the sector coverage and capacity performance (amongst other network key performance indicators (KPIs), since the overall radio channel quality (indicated by the average signal to noise and interference ratio (SNR) levels delivered to the mobile devices of users served) is reduced. Existing radio planning processes, which define and select the direction of the finite amount of radio power in the 3-dimensional antenna radiation space, can introduce inefficiencies due to simulation approximations, user mobile distribution and behaviours and implementation inaccuracies that impact base station performance in the network.
It is an aim of the present invention to mitigate at least some of the above mentioned drawbacks.